/Engine/Source/Runtime/Engine/Public/Subsystems/SubsystemCollection.h
Get a list of Subsystems by type
template<typename TSubsystemClass> const [TArray](API\Runtime\Core\Containers\TArray)< TSubsystemClass * > & GetSubsystemArray ( const [TSubclassOf](API\Runtime\CoreUObject\Templates\TSubclassOf)< TSubsystemClass > & SubsystemClass ) const